title: Patterned enzymatic degradation of poly(ε-caprolactone) by high-affinity microcontact printing and polymer pen lithography.
abstract: This paper reports deposition of Candida antarctica Lipase B (CALB) on relatively thick poly(ε-caprolactone) (PCL) films (300-500 nm) to create well-defined patterns using two different writing techniques: high-affinity microcontact (HA-μCL) and polymer pen (PPL) lithography. For both, an aqueous CALB ink is absorbed onto a polydimethylsiloxane (PDMS) writing implement (PDMS stamp or a PDMS pen tip), which is transferred to a spun-cast PCL film. HA-μCL experiments demonstrated the importance of applied pressure to obtain high-resolution patterns since uniform contact is needed between raised 20 μm parallel line regions of the PDMS stamp and the surface. AFM imaging shows pattern formation evolves gradually over incubation time only in areas stamped with CALB cutting through spherulites without apparent influence by grain boundaries. Strong binding of CALB to PCL is postulated as the mechanism by which lateral diffusion is limited. PPL enables formation of an arbitrary image by appropriate programming of the robot. The PDMS pen tips were coated with an aqueous CALB solution and then brought into contact with the PCL film to transfer CALB onto the surface. By repeating the ink transfer step multiple times where pen tips are brought into contact with the PCL film at a different locations, a pattern of dots is formed. After printing, patterns were developed at 37 °C and 95% RH. Over a 7-day period, CALB progressively etched the PCL down to the silicon wafer on which it was spun (350 nm) giving round holes with diameters about 10 μm. AFM images show the formation of steep PCL walls indicating CALB degraded the PCL film in areas to which it was applied. This work demonstrates that high-resolution patterns can be achieved without immobilizing the enzyme on the surface of polymeric stamps that limits the depth of features obtained as well as the throughput of the process.
authors.affiliation: NSF I/UCRC for Biocatalysis & Bioprocessing of Macromolecules, Polytechnic Institute of NYU, Six Metrotech Center, Brooklyn, New York 11201, USA.
authors.forename: Manoj
authors.initials: M
authors.lastname: Ganesh
authors.forename: Jonathan
authors.initials: J
authors.lastname: Nachman
authors.forename: Zhantong
authors.initials: Z
authors.lastname: Mao
authors.forename: Alan
authors.initials: A
authors.lastname: Lyons
authors.forename: Miriam
authors.initials: M
authors.lastname: Rafailovich
authors.forename: Richard
authors.initials: R
authors.lastname: Gross
mesh_terms: D005656:Fungal Proteins / Q000737:chemistry*; D006813:Humidity; D006868:Hydrolysis; D008049:Lipase / Q000737:chemistry*; D008567:Membranes, Artificial; D018625:Microscopy, Atomic Force; D011091:Polyesters / Q000737:chemistry*; D011327:Printing / Q000379:methods; D013499:Surface Properties
chemical_list: D005656:Fungal Proteins; D008567:Membranes, Artificial; D011091:Polyesters; C016240:polycaprolactone; D008049:Lipase; C431349:lipase B, Candida antarctica